Pressure retaining valve device



17 Q Q ARMER 2,@24 @85 PRESSURE RETAINING VALVE DEVICE Fi led March 17,1952 [III , I H a q N g 4 Q m i? L k g 5 E INVENTOR.

CLYDEC. FARMER BY ,g% 4% A TTORNE Y.

LOW PRESSURE Patented Dec. 17, 1935 UNITED STATES PATENT OFFICE PRESSURERETAINING VALVE DEVICE Application March 17, 1932, Serial No. 599,374

4 Claims. (Cl. 303-79) This invention relates to a fluid pressureretaining valve device of the type employed with fluid pressure brakesystems for retaining fluid pressure in the brake cylinder.

With the present standard so-called three position retaining valve, whenthe handle points vertically downward, the brake cylinder pressure iscompletely released in a predetermined time, for example about fourseconds, after the triple valve moves to its release position. With theretaining valve handle in 45 angle position from the vertical, the brakecylinder pressure is permitted to reduce at a very slow rate and isprevented from reducing below twenty pounds by the closure of a springloaded valve. With the retaining valve handle in horizontal position,the brake cylinder pressure is permitted to reduce at a restricted butsomewhat faster rate than was just described for the 45 angle positionand the brake cylinder pressure is prevented from reducing below tenpounds by the closure of a spring loaded valve.

The closing value just given for the retaining positions is necessary ontrains of considerable length on descending grades of considerablepercentage to avoid the brake cylinders becoming empty within thatperiod of time which is required for the recharge of the auxiliaryreservoirs. Should the brake cylinder be permitted to become emptyduring a recharging period, the succeeding brake pipe reduction mustexceed five pounds before any retarding force is again developed. Wherethe retaining valve closes the exhaust and holds twenty or ten pounds inthe brake cylinder, the lightest succeeding brake pipe reduction whichwill cause the triple valves to move to their application positions willimmediately produce an increased retarding force on the cars.

With the retaining valve turned to one of its retaining positions, thebrake cylinder pressure is permitted to reduce rather slowly to theclosing value of the retaining Valve and this amount of cylinderpressure and retarding iorce then becomes permanently active to preventexcessive acceleration of the train while the auxiliary reservoirs arebecoming fully recharged.

Under retaining valve operation as described, it will be obvious that,when a train on which the retaining valves are turned to retainingposition reaches a level track grade or an adverse grade, the train willbe stalled unless the retaining valves are turned down. Again, as isquite common on a considerable amount of main line track, a train mustmove over a generally descending grade of small degree, say one andone-half per cent or less. The closing value of the retaining valve ineven its ten pound position provides more retarding force within thetrain than that with which it can be kept in motion, the result of 5which is that either a portion of the retaining valves must be left intheir direct exhaust position or an attempt made to so manipulate thebrakes in the train as to secure safe control without the use ofretaining valves. Both of these 10 latter methods are practiced but bothare objectionable.

Where only a portion of the retaining valves are employed, all of thebrake work in controlling the train will be concentrated on the wheelsof the 15 cars on which the retaining valves are in retaining position,thus creating an undesirable amount of heat in the wheels of such cars.Again, when a train so operated must be moved for a distance over levelor even adverse grade, as is quite 20 common, trainm-en must go over thetrain and turn all retaining valves to direct release position and then,when the train is again entering the descending grade, they must go backover the train and again turn the needed number of re- 25 taining valvesto retaining position.

Another objectionable feature of such an arrangement for controllingtrain speed is that the consumption of air by the cars having retainingvalves turned down is as great as though the 30,

brakes on these cars were efiective, whereas they normally in no waycontribute to the control of the train speed.

Where trains and particularly long trains are controlled over such lowand undulating grades, 35 as just described, and without the use ofretaining valves, the time between brake applications is usuallyinsufiicient to accomplish the recharge of other than the brakes on thefront portion of the train and, therefore, as with only a portion 40 ofthe retainers turned up, the brake work is concentrated on the frontportion of the train, and in addition to this, the consumption of airrequired for controlling the train greatly exceeds the amount needed forcontrol when a portion of 45 the retaining valves are employed, aspreviously described.

The principal object of my invention is to provide a retaining valvedevice having means for overcoming the above difliculties and for this50 purpose, the retaining valve device is provided with a fourthposition, in which fluid under pressure is released from the brakecylinder at a predetermined slow rate which, to accomplish an increasein flexibility for the control of trains 55 on the light grades, is at asomewhat faster rate than provided for in the ten pound retainingposition.

In addition, this fourth position of the retaining valve will not have aclosing value and consequently in some given period, say sixty seconds,after release movement of the triple valve, the brake cylinder pressurewill have reduced from sixty tofive pounds, with which latter pressurethe retarding force of the brake becomes substantially nil. Havingretainers provided with the fourth position and all of them in a trainplaced in this position, sixty seconds time will be available forrecharging the auxiliary reservoirs of the cars before the brake pistonscan recede in their cylinders, and, therefore, if the brakes are thenreapplied all of the brakes in the train will immediately developeffective retarding force.

With the retaining valves of this type and used as described, if thetrain is approaching a level or adverse section of the generallydescending grade, a brake release is initiated in time, all brakecylinder pressure will be exhausted, and consequently the train will beas free to move over the level or adverse grade section as though theretaining valves were in their direct release position.

In the accompanying drawing; Fig. 1 is a central sectional view of apressure retaining valve device, embodying my invention, showing thecontrolling valve in the quick release position; and Fig. 2 anelevational view of the retaining valve device, partly in section, toshow the controlling valve in the slow release position.

As shown in the drawing, the pressure retaining valve device maycomprise a casing I in which is mounted a pair of spring loaded pressureretaining valves 2 and 3, and a controlling plug valve 4. The valve 2 isprovided with a stem 5 which is guided in a bore of a cap nut 6, havingscrew-threaded engagement in the casing and the valve 3 is provided witha stem 1 which is guided in a bore of a cap nut 8, having screw-threadedengagement in .the casing A coil spring 9 mounted in chamber l0 andsurrounding the stem 5, is interposed between a wall of the nut 6 and acollar carried by the stem 5 to hold the valve 2 seated against apredetermined pressure, and a coil spring l2 mounted in chamber l3 andsurrounding the stem 1, is interposed between a wall of the nut 8 and acollar l4 carried by the stem 1, to hold the valve 3 seated against apredetermined pressure.

The valve 2 controls communication from a passage l5 leading to the seatof plug valve 4, to chamber H], and valve 3 controls communication froma passage IE to chamber l3, the passage I6 communicating with a passageleading to the seat of plug valve 4.

Chamber I0 communicates with a passage l8 leading to passage through arestricted port l9 in a choke plug 20 which is mounted in passage l8,and chamber l3 communicates with the atmosphere through a restrictedport 2| in a choke plug 22.

The plug valve 4 is provided with an operating handle 23 and has fouroperating positions as follows: quick release, high pressure, lowpressure, and slow release.

In the quick release position, as shown in Fig. 1, the plug valve 4 isso positioned that a through port 24 therein connects a chamber 25,

open to pipe 26 (which pipe is connected to the usual brake cylinderexhaust of the usual triple valve device) (not shown), to an atmosphericexhaust port 21, so that with the plug. valve 4 in this position, fluidreleased from the brake cylinder, upon movement of the triple valvedevice to release position, is vented directly to the atmosphere at arapid rate, say such that the brake cylinder pressure will be completelyreleased in about four seconds.

When the plug valve 4 is turned to the high pressure position, the port24 connects chamber 25 with passage i5, so that fluid released from thebrake cylinder first acts to unseat the valve 2 against the pressure ofspring 9 and then flows from chamber I0 through restricted port I9, andpassages l8 and I! to passage l6. The valve 3 is then unseated by fluidpressure against the pressure of spring I2 and fluid under pressureflows to chamber l3 and thence to the atmosphere through restricted port2|. When the brake cylinder pressure has been reduced to a predetermineddegree, say twenty pounds, the valves 2 and 3 will close, thus retaininga pressure of twenty pounds in the brake cylinder.

When the plug valve 4 is turned to the low pressure position, the port24 connects chamber 25 with passage so that fluid released from thebrake cylinder only has to flow past the valve 3 tothe atmosphere. Whenthe brake cylinder pressure has been reduced to a predetermined lowdegree, such as ten pounds, the valve 3 will seat and cut off thefurther release of fluid from the brake cylinder.

As so far described, the positions and operation of the retaining valvedevice are the same as the retaining valve devices now employed inservice, but according to my invention, a fourth position of the plugvalve 4 is added in which fluid may be released from the brake cylinderdirectly to the atmosphere at a slow rate. In this position, as shown inFig. 2, a cavity 33, cut in the valve 4 and opening into the passage 24,provides communication in this fourth position from chamber 25 to port24. In this position, communication is established from port 24 toatmospheric exhaust port 21 by way of a restricted port 3|, the port 3|opening into port 24 and leading to a port 32 of greater area whichopens at the seat of the plug valve 4.

The flow area of restricted port 3| is such that fluid will be releasedfrom the brake cylinder at a somewhat greater rate than fluid isreleased from the brake cylinder in the low pressure position, but yetat a sufficiently slow rate to permit the auxiliary reservoir on thecars throughout the train to be recharged with the triple valves inrelease position and at the same time retain suflicient pressure in thebrake cylinder to prevent undue acceleration of the speed of the train.

The fourth or slow release position is defined by the engagement of thehandle 23 with a stop pin 33, which is secured in the casing at theproper position.

In order to convert a retaining valve device of the existing type to theimproved type, a stop lug on the existing retaining valve device whichdefines the low pressure position is cut off and the casing is drilledto provide a bore into which the pin 33 is driven.

The plug valve of the existing type of retaining valve device ismachined to provide the cavity 30 and the restricted port 3 I, sopositioned that in the fourth position, communication will beestablished from the chamber 25 to the exhaust port 21.

While one illustrative embodiment of the invention has been described indetail, it is not my intention to limit its scope to that embodiment orotherwise than by the terms of the appended claims.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. A pressure retaining valve device comprising a loaded pressureretaining valve device and a manually operable plug valve having athrough port, through which fluid flows from a fluid pressure inlet tothe atmosphere at a rapid rate in one position of the valve, and throughwhich fluid flows from the inlet past the loaded pressure retainingvalve to the atmosphere in another position of the valve, said valvehaving a restricted port communicating with said through port, and withthe atmosphere in a third position of the valve, and said through porthaving an extended cavity which communicates with the fluid pressureinlet in said third position, whereby communication is established insaid third position from the fluid pressure inlet, through a restrictedport, to the atmosphere.

2. A pressure retaining valve device comprising a loaded pressureretaining valve and a manually operable plug valve having a portembodied therein for establishing a communication from a fluid inlet insaid valve device to a fluid outlet in said valve device, through whichcommunication fluid may flow at a relatively unrestricted rate when saidplug valve is in one position, said plug valve having also embodiedtherein a restricted port for restricting the rate of flow of fluid fromsaid fluid inlet to the said fluid outlet below said relativelyunrestricted rate when said plug valve is in another position, saidvalve device being provided with a restricted port for restricting therate of flow of fluid from said fluid inlet to a second fluid outletthrough said pressure retaining valve below the restricted rate effectedby the restricted port in said plug valve, when said plug valve isfurther operated to an- 5 other position.

3. A pressure retaining valve device comprising a casing having a fluidinlet and two different fluid outlets, a loaded pressure retaining valvecontrolling a communication for the flow of fluid from the said fluidinlet to one of said fluid outlets, and a manually operable plug valvehaving a port therein adapted in one position of said plug valve toestablish said communication, the said plug valve having a port adaptedin a second position of the plug valve to establish a com munication forthe flow of fluid from said fluid inlet to the other of said outlets,and having also a restricted port adapted in a third position of saidplug valve to establish a. communication through which fluid flows fromsaid fluid inlet to said other fluid outlet at a lesser rate than in thesaid second position of said plug valve.

4. A pressure retaining valve device comprising a casing having a fluidinlet and two different I fluid outlets, a pair of pressure retainingvalves loaded at difierent values, respectively, and controlling twodifferent communications, respectively, between said fluid inlet and oneof said fluid outlets, and a manually operable plug valve having a portadapted in a first and a second position, respectively, of said plugvalve to establish said two communications, said plug valve having aport adapted in a third' position of said plug valve to establish acommunication through which fluid flows at a certain rate from saidfluid inlet to the other of said outlets, and having also a restrictedport adapted in a fourth position of said plug valve to establish acommunication through which fluid flows from said fluid inlet to 40 saidother fluid outlet at a slower rate than said certain rate.

CLYDE C. FARMER.

